Wind turbine and wind turbine foundation

ABSTRACT

A wind energy plant is provided with a foundation base and a tower which is placed on the foundation base. The foundation base has a foundation plate below ground level and a foundation plinth on the foundation plate above ground level. On the foundation plinth a tension cord connector is provided with a plurality of bores for receiving tension cords. The tension cords are tensioned on an underneath side of the connector by means of a tension cord head. The foundation plate and the foundation plinth are cast in one piece from site-mixed concrete.

BACKGROUND

1. Technical Field

The present invention relates to a wind energy plant and to a windenergy plant foundation base.

2. Description of the Related Art

Before a tower of a wind energy plant is erected, a correspondingfoundation base has to be provided in the ground. The foundation base istypically cast, for example, with concrete on site. After the concretehas hardened a first tower segment can be placed on the foundation base.

FIG. 2A shows a diagrammatic illustration of a foundation base of a windenergy plant according to the prior art. A foundation base 210 cast ofconcrete has an ingate 210 c or a cast ring 210 c which has a bore 210 bfor receiving a tensioning cable 230. The ingate 210 c is therebylocated underneath the ground. The wall of the tower segments 102 isprovided with a plurality of bores 102 a through which the relevanttensioning cables or tension cords 230 can be guided. These tensioncords 230 are used to tension the segments of the tower of the windenergy plant. At the lower end 210 d of the ingate 210 c there is atleast one tension cord head 240. A basement or a further space 210 a canbe provided underneath the ingate 210 c where the tension cords 230 canbe pretensioned by means of the tension cord head 240. With theembodiment of FIG. 2A an internal tensioning is shown, i.e. the tensioncords run inside the tower wall.

FIG. 2B shows a diagrammatic illustration of a foundation base of a windenergy plant according to the prior art. The foundation base 210 is castof concrete and has an ingate 210 c with at least one bore 210 b for thetensioning cable or the tension cord 230. As opposed to FIG. 2A thetension cord 230 is not guided inside the formwork of the tower, butinside the tower and outside of the tower wall so that this is aninternally tensioned or externally tensioned tower respectively. Asshown in FIG. 2A the ingate has an underneath side 210 a where a tensioncord head 240 is provided for tensioning the tension cord or tensioningcable. Earth, gravel 10 or the like can be provided at least in partabove the concrete foundation base 210.

In order to be able to tension the tension cords 230 by means of thetension cord head a foundation basement 210 a, i.e., a space belowground level, has to be provided.

BRIEF SUMMARY

One or more embodiments of the present invention provide a wind energyplant with an improved foundation base and an improved wind energyfoundation base respectively.

A wind energy plant is provided with a foundation base and a tower whichis placed on the foundation base. The foundation base has a foundationplate and a foundation plinth on the foundation plate. A tension cordconnector is provided on the foundation plinth and has a plurality ofbores for receiving tension cords. The tension cords are tensioned on anunderneath side of the connector by means of a tension cord head. Thefoundation plate and the foundation plinth are cast from concrete, andthe foundation plinth can project above the ground, whilst thefoundation plate is located underneath the ground.

The distance between the upper side of the concrete plate and anunderneath side of the tension cord connector is large enough so thatthe workers have enough space to tension the tension cords.

According to a further aspect of the present invention the foundationplate and the foundation plinth are cast in one piece from site-mixedconcrete.

The invention likewise relates to a wind energy plant foundation basehaving a foundation plate and a foundation plinth on the foundationplate. An ingate is provided on the foundation plinth with a pluralityof bores for receiving tensioning cables or tension cords. Thetensioning cables or tension cords are tensioned on an underneath sideof the ingate by means of a tension cord head. The foundation plate andthe foundation plinth are cast from concrete and can project above theground.

One or more embodiments of the invention relates to the idea ofproviding a concrete foundation base with a concrete plinth andproviding the ingate for the tension cords on the plinth. The plinth ishereby disposed above the foundation base.

In order to erect a wind energy plant or a tower of a wind energy plant,first the foundation base is provided and then tower segments are placedon the foundation base. The tower segments and the foundation base arethen connected by tension cords to a static system. The tower segmentsas well as the foundation base can be manufactured and suppliedseparately. Through the foundation base it is possible to dispense witha foundation basement as well as with a foundation base cover. Thefoundation bases can be constructed flatter so that building costs,excavation and construction time can be considerably reduced.

One or more embodiments invention further relates to the idea of castinga lower tower segment directly together with the foundation base fromconcrete or site-mixed concrete so that the foundation base comprises afoundation plate and on the plate a plinth or a segment which is adaptedto a foundation base placed thereon and is arranged above the foundationbase or above the ground. An ingate is provided on the plinth or thesegment with a plurality of bores for receiving a tensioning cable or atension cord. The foundation base can be used both for the internaltensioning or for the external tensioning (inside the tower).

According to one embodiment of the invention the plinth or the segmentis cast in the form of a lower tower segment of the tower together withthe foundation base. The plinth projects optionally above the ground orground level. This is advantageous because then no foundation basementneed be provided and there is sufficient space to tension the tensioncords by means of a tension cord head.

Further configurations of the invention form the subject of thedependent claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Advantages and embodiments of the invention will now be explained infurther detail below with reference to the drawings.

FIG. 1 shows a diagrammatic illustration of a wind energy plantaccording to the invention;

FIG. 2A and 2B each show a diagrammatic sectional view of a foundationbase of a wind energy plant according to the prior art;

FIG. 3 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a first embodiment;

FIG. 4 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a second embodiment;

FIG. 5 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a third embodiment;

FIG. 6 shows a diagrammatic illustration of a foundation base of a windenergy plant according to a fourth embodiment;

FIG. 7 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a fifth embodiment, and

FIG. 8 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a sixth embodiment.

DETAILED DESCRIPTION

FIG. 1 shows a diagrammatic illustration of a wind energy plantaccording to the invention. The wind energy plant 100 comprises a tower102 and a nacelle 104. A rotor 106 on the nacelle 104 is provided withthree rotor blades 108 and a spinner 110. During operation the rotor 106is set in a rotational movement through the wind and thus also turns therotor or armature of the generator in the nacelle 104. The pitch angleof the rotor blades 108 can be changed by pitch motors at the rotorblade roots of each respective rotor blade 108.

FIG. 3 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a first embodiment. The foundation base210 of the wind energy plant has a foundation plate 211 with afoundation plinth or foundation segment 212. The foundation plinth orfoundation segment 212 is circular in design and serves for supporting afirst tower segment 102 a thereon. The foundation plinth or thefoundation segment 212 projects above the ground or ground level 10whilst the foundation plate 211 is provided below ground level.

A tension cord connector is provided on the foundation plinth orfoundation segment 212 optionally in the form of an ingate 213 with aplurality of bores 213 a each for receiving a tension cord or tensioningcable 230. A first tower segment 102 a of a tower of the wind energyplant can be placed on the foundation plinth or foundation segment 212.

The first embodiment shows an internal tensioning of the tower segmentsof the tower of the wind energy plant since the tensioning cables ortension cords 230 run inside the tower wall or the tower segments.

FIG. 4 shows a diagrammatic illustration of a foundation base of a windenergy plant according to a second embodiment. The foundation 210comprises a foundation plate 211 (below ground level) and a foundationplinth or a foundation segment 212 (above ground level). On thefoundation plinth or foundation segment 212 a tension cord connector isprovided optionally in the form of an ingate 214 with a plurality ofbores 214 a which are used for receiving the tension cords or tensioningcables. A tension cord head 240 for tensioning the tension cords 230 isprovided at a lower end 214 b of the ingate 214.

According to the second embodiment an external tensioning is shown sincehere the tensioning cables are provided not within the tower wall, butoutside of the tower wall but inside the tower.

The wind energy plant foundation bases according to the first and secondembodiments differ essentially through the configuration of the ingate213, 214 which are each provided to allow tensioning of the tensioncords or tensioning cables. The ingate or tension cord connector 213,214 is arranged optionally above the ground 10 or ground level. Afoundation basement can thus be avoided. The ingate 213, 214 accordingto the first or second embodiment can be provided as a ring which canextend along the entire periphery of the tower.

Optionally the distance between an upper end 211 a of the foundationplate 211 and a lower end 213 b, 214 b of the ingate 213, 214 can amountto at least a meter. The height of the ingate 213, 214 can optionallyamount to at least a meter.

The tension cord connector can optionally be designed as an ingate 214and can be cast together with the foundation plate 211 and the plinth212.

According to a third to sixth embodiment of the invention a foundationplinth or foundation segment is not cast of concrete together with theremaining foundation base, but is designed as a steel tower footsection.

FIG. 5 shows a diagrammatic sectional view of a wind energy plantfoundation base according to a third embodiment. Several segment anchors270 and threaded rods 290 are provided in a concrete foundation base 11and project beyond the foundation base 11. A joint 280 (e.g., a hardconcrete joint) can be provided on the foundation base 11 on which afoundation segment 260, e.g., in the form of a peripheral steel adapteris provided. The steel adapter 260 has a lower end 261, an upper end 263as well as a side or sleeve face 262. A plurality of bores 267 areprovided in the upper end 263. The bores 267 serve to receive thetension cords or tensioning cables 230. The tower segments of the windenergy plant tower 102 have on the inside several bores through whichthe tension cords or tensioning cables 230 can be guided. The tensioncords or tensioning cables can be tensioned by means of a tension cordhead 240 which is provided on the underneath side of the upper end 263of the steel adapter 260.

According to the third embodiment an internal tensioning of the tower ofthe wind energy plant is provided.

FIG. 6 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a further embodiment. The foundationaccording to the fourth embodiment corresponds substantially to thefoundation base according to the third embodiment wherein the upper end265 is made longer. The upper end 265 has a plurality of bores 265 awhich are provided for receiving the tension cords or tensioning cables230. A tension cord head 240 is provided underneath the upper end 265for tensioning the tension cords or tensioning cables.

According to the fourth embodiment an external tensioning of the towersegments is thus provided wherein the tension cords or tensioning cables230 are located inside the tower.

According to the third and fourth embodiments the steel adapter 260 canbe filled with a Pagel mass 264 which is advantageous as regardsstrengthening the adapter as soon as the Pagel mass is hardened.

According to the third and fourth embodiments the segment anchor 270 canbe configured as an anchor ring.

According to a fifth and sixth embodiments a foundation section isprovided which is anchored in part in the foundation base. An upper endof the foundation section has a plurality of bores for receiving thetension cods or tensioning cables which are then tensioned by means of atension cord head.

FIG. 7 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a fifth embodiment. A foundation section260 has a lower end 261 and an upper end 263 as well as a side or sleeveface 262. The lower end 261 of the foundation section is placed at leastin part in a concrete foundation base 11. The upper end 263 has aplurality of bores 263 a. A lower tower segment of a tower 102 of thewind energy plant can be placed on the upper end 263. A plurality ofbores 102 a are provided in the wall of the tower segment. Tensioningcables can be inserted through the bores 102 a and the bores 263 a andcan then be tensioned by means of a tension cable head 240.

According to the fifth embodiment internal tensioning is provided.

The foundation section 260 can have a reinforcement plate 264. Thefoundation section 260 can be made from metal.

FIG. 8 shows a diagrammatic sectional view of a foundation base of awind energy plant according to a sixth embodiment. The foundation baseaccording to the sixth embodiment corresponds to the foundation baseaccording to the fifth embodiment wherein the upper end of the towersection is made longer so that a section of the upper end 265 projectsinto the tower and has there a plurality of bores 265 a through whichtension cords or tensioning cables 230 can be guided so that these canthen be tensioned by a tension cord head 240.

The foundation section 260 can have a reinforcement plate 264.

According to the sixth embodiment an external tensioning is thusprovided wherein the tensioning cables run in the interior of the tower.

1. A wind turbine comprising: a foundation having a portion in a groundand a portion above a ground level, the foundation including afoundation plate and a foundation plinth that extends from thefoundation plate and above the ground level, wherein the foundationplate and the foundation plinth are cast in a single piece of concrete;a tension cord connector provided on the foundation plinth, the tensioncord connector including a plurality of bores for receiving tensioncords, wherein the tension cords are tensioned at a lower surface of thetension and cord connector by a tension cord head; and a tower locatedon the foundation.
 2. The wind turbine according to claim 1 wherein anupper side of the concrete plate is spaced from a lower side of thetension cord connector or a position of the tension cord head by adistance.
 3. The wind turbine according to claim 2 wherein a height ofthe tension cord connector is the same as the distance between the upperside of the concrete plate and the lower side of the tension cordconnector or the position of the tension cord head.
 4. A wind turbinefoundation base, comprising: a foundation plate located below groundlevel; and a foundation plinth that is integral with and extending fromthe foundation plate above ground level, wherein on the foundationplinth is a plurality of bores for receiving tension cords, wherein thetension cords are tensioned on a lower surface of the connector by atension cord head.
 5. The wind turbine foundation base according toclaim 4 wherein the foundation plate and the foundation plinth areformed from concrete.
 6. The wind turbine foundation base according toclaim 4 wherein the lower surface of the connector is above and spacedapart from the foundation plate by a distance.
 7. The wind turbinefoundation base according to claim 6 wherein tension cords are spacedfrom the foundation plate.
 8. The wind turbine foundation base accordingto claim 4 wherein the foundation plinth extends from a middle portionof the foundation plate.